Hot Rod Forum banner

Carb Spacer or Not?

4K views 7 replies 6 participants last post by  IanRiordan 
#1 ·
What are the advantages/disadvantages of running a one inch spacer under a carb. Clearance is not an issue in this case.
 
#3 ·
I have had good luck with one on a '64 with a nothing special 350. It is turning 13.49 with 3.73 gears and a higher than normal convertor. Your choice, I have one I will put on mine to increase plenum volume. I am for them when a better manifold cannot be easily had.
 
#6 ·
To space or not to space

It all depends on what kind of spacer you are using. If you use a spacer with 4 throttle holes in it, this will tend to help your bottom and mid range power, with little or no help on top end, where a spacer with an open plenum, or big hole will tend to help your mid and top end, with little or no help to the bottom end.
The reason the 4 hole will help bottom end is that it keeps the velocity up at lower rpm, while the one hole jobs act to increase the size of your plenum chamber ( or chambers if you have a dual plenum intake), and large plenums are very useful for high end power increases.
The one with the one big hole, would probably have more effect on your engine, particularly on top end than the 4 hole variety would on your lower and mid range. The thing to be careful of is that while it may help your top end, the one holer may harm your lower end power. Its all a matter of compromises and what your desired end result may be.
 
#8 ·
If a spacer helps, then your carb or manifold is too small for your package, if it hurts too big. use a spacer as a tuning device. generaly if a four hole helps more than an open one the carb is too small and vice versa. Remember, comp, stroke, rod length etc play a major role in controlling air speed. Just use spacers to dial in your car, then make appropriate changes.... unless your class won't allow them.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top